Authorities in Western Australia are continuing their hunt for a great white shark believed to be responsible for a fatal attack on a 17-year-old boy at Cheynes beach on the state’s south coast on Monday.

Jay Muscat died after being bitten on the leg by a shark while spearfishing with his friend, Matt Pullella, at a popular fishing spot known as Three Stripes.

Pullella, who fired his speargun into the mouth of the shark when it turned to him after biting Muscat, identified the shark as a four- to five-metre great white.

The Department of Fisheries deployed drumlines in the water around Cheynes beach, 65km east of Albany and 490km south-east of Perth, on Tuesday morning after efforts to catch a great white on Monday failed.

The department said it was “investigating and will again deploy equipment today in an effort to catch the shark (most likely to be a white shark).”

Two sets of drumlines – baited shark hooks – were in the water for four hours after Monday’s attack and the beach remains closed.

The department’s acting director-general, Dr Rick Fletcher, said on Monday it was possible Pullella had fatally injured the shark with his spear gun.

He said fisheries staff were searching for a great white of the right size in the area, and any shark that fitted that description would be killed.

“If they [fisheries staff] catch a shark that’s of similar species and similar length to that one likely to be in the attack, then it will be killed,” he said.

Fletcher told ABC local radio in Perth on Tuesday morning it was unlikely fisheries staff would be able to positively identify a shark killed as the one responsible for the attack on Muscat.

“In most cases you probably can’t identify it specifically but what we will be doing is any shark that fits within the serious threat policy … it will be disposed of as per the policy,” he said.

“Obviously if we find a shark with a spear in it that’s clear cut, but that’s probably unlikely.”

Fletcher said one fisheries boat was dragging baited lines off Cheynes beach and another boat was searching shallow water for signs of an injured shark.

The set lines are being used in place of drumlines, contrary to previous reports.

Natalie Banks, the chairwoman of the group No WA Shark Cull, told Guardian Australia the department’s actions were akin to going down to the park after a dog attack and “shooting any dog that looks dangerous”.

“Somehow the government believes that if we kill a shark the public may feel safer, but it’s a false sense of security,” she said. “I don’t know of any other state or country that believes in the revenge killing of sharks.”

Under WA’s serious threat policy, the Department of Fisheries is authorised to kill any shark deemed to be a “serious threat”.

It authorises the culling of any great white, tiger or bull shark that is more than three metres long and either believed to have been responsible for an attack, or reported several times in the same area less than one nautical mile offshore.

The policy’s precursor, the “imminent threat” policy, was introduced in September 2012 after a sharp increase in the number of fatal shark attacks.There have been 12 fatal shark attacks in WA since 2000, and eight of those occurred in the past four years.

The policy was rebadged this month as the “serious threat” policy after the government acknowledged it was inaccurate to call a policy that allowed the hunting of a shark several hours after an attack had occurred and beaches had closed “imminent”.

In October, fisheries authorised the destruction of two juvenile great white sharks near Esperance after 23-year-old surfer Sean Pollard lost his left arm and right hand in an attack. In that case the attacking shark was identified as a great white by the bite marks on Pollard’s surfboard.

This month the government revealed it had used radio location pings from scientific tags to identify a shark as a serious threat and approve its destruction. However that shark avoided capture.